Method for presetting a lathe tool

ABSTRACT

A cross tool slide with a master bar is set in a zero position in the main axis of a lathe whereupon indicating counters for the distance of displacement of the slide are set to zero. A tool is substituted for the master bar and also set to a zero position by a gauge on the slide so that the movements of the slide and tool for machining a workpiece are indicated by the indicating counters.

United States Patent [72] lnventor Romeu Romi Sao Paulo, Brazil [21]Appl. No. 84,793 [22] Filed Oct. 28, 1970 [45] Patented Nov. 30, 1971[73] Assignee lndustrias Roml S.A.

Sao Paulo, Brafll [32] Priority Nov. 16, 1966 [3 3] Brazil [31 184,575

Original application Nov. 1, 1967, Ser. No. 679,698, now Patent No.3,548,693. Divided and this application Oct. 28, 1970, Ser. No. 84,793

[54] METHOD FOR PRESE'ITING A LATHE TOOL 8 Claims, 16 Drawing Figs.

[52] U.S.Cl 82/1 C, 29/591 8 Primary Examiner-Leonidas VlachosAttorney-Michael S. Striker ABSTRACT: A cross tool slide with a masterbar is set in a zero position in the main axis of a lathe whereuponindicating counters for the distance of displacement of the slide areset to zero. A tool is substituted for the master bar and also set to azero position by a gauge on the slide so that the movements of the slideand tool for machining a workpiece are indicated by the indicatingcounters.

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INVENTOR ATTORNEY METHOD FOR PRESE'I'TING A LATHE TOOL This applicationis a division of my application Ser. No. 679,698 filed Nov. 1, 1967, andnow U. S. Pat. No. 3,548,693.

SUMMARY OF THE INVENTION This invention relates to a method forpresetting lathe toolholders, and more particularly to a zero referencepositioning means for lathe toolholders which are combined with directreading diameter indicators.

According to one method of the invention, the lathe toolholder ispositioned by the steps of determining the geometric axis of the lathemain spindle by a geometric axis determining device; setting by means ofa stop in the main axis a first gauge attached to said geometric axisdetermining device, the pointer thereof being set at zero for subsequentsettings; attaching to the toolholder a master bar; advancing a toolpostand said master bar so that one end thereof touches a sensor of thefirst gauge already set; setting counter means indicating displacementsof the slide carrying the toolpost to zero indication; mounting a toolzero setting device on the upper face of the cross-slide, a second gaugeon which being set as the sensing member thereof touches said master barend; substituting a tool for the master bar in the toolpost and settingsuch tool at the same overhang already determined for the master bar;applying to a platform in the tool zero-setting device a tool heightfixing means and fixing the tool height fixing means for subsequentsettings of the tool; withdrawing the cross-slide and attachedtoolholder, setting up the workpiece; and advancing the cross-slide andthe tool on the workpiece until said workpiece has a predetermineddiameter as observed from the reading at the indicators.

Axis determination means are provided to determine in a lathe the mainspindles geometric axis, both in the vertical and in the horizontalplanes, said means to be used whenever a recheck of the position of thegeometric axis is desired.

Again there is provided a means to determine the height at which thecutting edge of the tool must be adjusted which means includes a lockingelement to hold said means in a set position wherein it serves as areference for subsequent resetting of the tool height.

. For a given setting of the tool the overhang of the tool, i.e., theextension which projects from the toolpost, measured between thetoolpost and the cutting edge is permanent.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a front elevation of theapparatus embodying the invention;

FIG. 2 is a sectional view taken on the line AA of FIG. 1;

FIG. 3 is a sectional view taken through the line BB of FIG. 1;

FIG. 4 is a sectional view taken through the line CC of FIG. 3;

FIG. 5 is a sectional view across the line DD of FIG. 3;

FIG. 6 is an enlarged cutaway view of a preloaded type crossfeed screwwith recirculating balls;

FIG. 7 is a sectional view taken along the crossfeed screw of the lathe;

FIG. 8 is an enlarged cutaway view of an axial thrust preventing meansfor making the crossfeed screw stable;

FIG. 9 is a front elevation of a device for locating the geometric axisof a lathes main spindle;

FIG. 10 shows a reference device for the zero setting of a dial providedin the device of FIG. 9;

FIG. 11 shows the geometric axis determination device as set by a masterbar used to fix the overhang of the tool;

FIG. 12 is a plan view of the assembly shown in FIG. 11 as viewed fromthe left, as shown in the drawings;

FIG. 13 is a plan view of the tool height fixing device;

FIG. 14 is a view taken on the line E-E in FIG. 13;

FIG. 15 is a side elevation of the tool zero-setting device; and

FIG. 16 is a plan view of the tool zero-setting device shown in FIG. 15.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings ahousing 1, FIGS. 1, 2, has a front wall from which projects a fractionalgraduation drum 2, as well as a flywheel 3, the first one used to governthe idle feeding and the second to control rapid feeding of the cuttingtool.

The housing is firmly secured to the front of the cross-sliderest in alathe which embodies this invention.

The fractional graduation drum 2 comprises an outer ring 4, on the rearportion of the periphery of which are engraved the fractionalgraduations 5 (FIG. 3) the use of which will be explained in detailhereinafter. On the front portions of said outer ring 4 are carvedknurles 6 to guarantee secure gripping of the idle feed control. In theinner face of said outer ring 4 shoulders 7, 8 are provided by which itis secured to a central annular support 9, which is formed with anannular rim l0, tightened against said shoulder 7. The central annularsupport 9 is centrally drilled with a conical bore ll to which isclosely adapted the taper end 12 of slow feed control shaft 13, which isthreaded at its outer end and has a locknut l4 screwed thereon fittingclosely in a round recess 15 milled in the middle portion of saidcentral annular support 9, the locknut 14 being provided with a split16. A screw 17 is screwed in the threads cut in a bore transverselydrilled in the legs formed by said split 15, which serves the purpose oflocking said nut 14 as well as the central annular support 9 relative tothe idle feed control shaft 13.

In a bore 18 laterally drilled in said support 9 is fitted a bolt 19,the outer end of which is provided with a knurled head 20, and the innerend with threads 21 which screw in threads cut in a perforation 22,bored in a lockring 23.

The assembly of the outer ring 4, the central annular support 9 and thelockring 23 may rotate guided by a projecting rim 24 provided in asupport disk 25 fitted into a round recess 26 provided in the front wallof housing 1.

A set of ball bearings mounted in a cylindrical member 27, formed in thefront wall of housing I, will support the smooth rotary movement of idlefeed control shaft 13, which in the middle portion is provided with acircular ring 28 in contact with inner ball bearing in order that saididle feed control shaft I3 be prevented from any axial shifting.

The inner end of the slow feed control shaft 13 is provided withindentations 29 which engage the teeth of a spur gear 30 mounted on ahub 31 also integrally formed with a spur gear 32 and in the conicalinner portion of which is closely fitted the taper end 33 of a crossfeedscrew 34, see FIGS. 2 and 7. The hub 31 is locked against axialdisplacement relative to the crossfeed screw 34 by means of a locknut 35which can screw on threads 36 cut in the outer end of the crossfeedscrew 34 and which is secured by a pin 37 fitting into aligned bores inthe locknut 35 and in the outer end of the crossfeed screw 34.

The second spur gear 32 mounted on the outer end of the hub 31permanently engages a spur gear 38 keyed in the end 39 of a rapid feedcontrol shaft 40, which rotates in a set of ball bearings mounted in acylindrical member 41, provided in the front wall of housing 1. By meansof a pin 42 the rapid feed control shaft 40 is secured firmly to the hub43 of the flywheel 3 which is provided with a handle 44 through whichthe flywheel 3 is turned.

The spur gear 30 engages teeth 45 provided in an intermediate shaft 46rotating in ball bearings, see FIGS. 3 and 5.

The shaft 46 has at one end 47 a bevel gear 48 firmly secured by a pin49 and engaging a second bevel gear 50 which is anchored to an outertransversely placed shaft SI, (FIG. 4) by means of setscrews 52 lockedby a set ring 53. The outer shaft 51 is supported by a bushing 54. whichis firmly fitted in a bore 55 disposed in a member 56, and lockedagainst axial displacement by means of a screw 57, and by the chamferedinner end 58 abutting the front face of hub of the bevel gear 50.

The shaft 51 has a flange 59 abutting the lateral wall of housing I. Theouter shaft 51 receives a concentric actuating shaft 60 which isprovided in the outer end 61 with indentations 62, 63 which may beselectively entered by a ball 64 resiliently engaged by a spring 65arranged in a cavity 66 radially drilled in a disc 67. The disc 67 isfirmly secured to a knurled knob 68, which is formed with an insideflange 69, the inner periphery of which is provided with serrationsarranged to engage selectively serrations provided in the periphery ofthe flange 59 of outer shaft 51. At the inner end of the shaft 60 lies abore 70 drilled in connecting sleeve 71 to which it is secured by meansof a pin 72. In the other end of the bore 70, an end 73 of a shaft 74 isinlaid and firmly secured by means of a pin 75.

The above-mentioned shaft 74 is a part of a digital and ordinalindicating counter 76 which is provided with a dummy wheel 77, the tenthrotation of which will change a character in the first order wheel ofthe digital indicating counter 76. The digital indicating counter 76 issupported by a platform secured to the wall of the housing I by means ofscrews 78. The readings of the digital indicating counter 76 may beobserved through a magnifying lens fitted to an aperture 80 provided inthe cover 81 of the housing 1.

The crossfeed screw 34 crosses the length of the slide 82 of the lathe.In the middle portion (FIG. 7), the slide 82 is provided with slots 83,84 arranged at the lower surface thereof, where it is supported slidablyby prismatic guide rails 85, 86, provided at the upper surface of themachine bed 87. The turning movements of crossfeed screw 34, by meansmounted in the apron of the lathe, cause the cross-slide 88, when thewheel 3 is rotated, to travel rapidly in a precise feed movement asdirected by the fractional graduation drum 2.

To execute the crossfeed movements, cross-slide 88 will travel to andfrom relative to the geometric axis of the lathe guided by meansprovided in the slide 82. The geometric axis is indicated in FIG. 7 bythe numeral 89 for the purpose of a clearer understanding .of thisexplanation. The crossfeed movements 'are derived from a cross-slidelead nut 90 (FIG. 6 and 7) which travels along the crossfeed screwguided in a channel cut in the slide 82, and is secured to cross-slide88.

To eliminate the play between the crossfeed screw 34 and the nut 90causing the shifting of cross-slide 88, in order that measurements beobtained with the smallest error, the crossfeed screw 34 is formed inits middle portion with a helical thread groove 91 whose cross sectionis semicircular, whereon can slide smoothly the nut 90 by means of arecirculating ball bearing 92 (FIG. 6), the ball bearing 92 comprising aleft sleeve 93 and a right sleeve 94. The left sleeve 93 has a neck atthe outer end, to which is threaded a collar 95, peripherally providedwith threads to be screwed in the inner threads of the cross-slide nut90. The right sleeve 94 similarly comprises a neck at the outer end, towhich is fitted a set collar 96 peripherally provided with outer threadsscrewed in the inner threads of the cross-slide leading nut 90. The leftsleeve 93 and the right sleeve 94 are provided internally with a helicalthread groove 97 whose cross section is semicircular, and which formswith thread groove 91 a helical channel having a circular cross section.In the channel thus formed balls 98 for the left hub 93, and the balls99 for the right hub 99 are free to circulate. As seen in FIG. 6 balls99 are held during the rotation of the crossfeed screw 34 by a guide 100and enter the left-hand connecting tube 101, whichtogether with therighthand connecting tube 102 extending helically in a contrary sense,cause then circulation from one portion of the channel and into aforward portion of said channel.

At the inner end the left and right sleeves 93, 94 are fastened togetherby flanges I03, 104 which are threaded in the periphery to be screwed inthe threads cut in the middle portion of the tubular part of thecross-slide nut 90. The space formed between the flanges I03. 104 may befilled up with sealing rings a of felt or suitable material to allow atrue adjustment between the respective sleeves 93, 94 by means of boltsand nuts 90b.

The crossfeed screw 34 must work with absolute axial precision, notallowing the least cam action, so as not to interfere by adding orsubtracting movement on the cross-slide means for each and every fullrevolution of the cross screw 34. To accomplish this precision, a set ofadjusting nuts is applied to an assembly of self-centering ball bearingsI07 and 108. At the smooth middle portion 105 (FIG. 7, 8) of the slenderpart in the end portion of crossfeed screw 34, a carrier ring 106 isfitted with the minimum of bore tolerance. The carrier ring I06 servesas a central support for the left ball bearing I07 and the right ballbearing 108. An outer flat face 109 of a left centering ring 110 placedat the outer left hand of the bearing I07, fits into a recess Ill, cutnear the upper portion of rear wall of the slide rest 82.

The left centering ring 1 10 is provided with a concave inner face 112,and the cap of the left ball bearing 107 has a convex face I 13 havingthe same radius of curvature in order to allow the sliding of thosesurfaces of each other when centering is effected.

Equally the right ball bearing 108 is centered by means of the rightcentering ring I14 comprising an outer flat face and a concave innerface 116 with the same radius of curvature as that of a convex face 117of the cap of the right ball bearing 108.

This bearing assembly is centered by slipping the mating surfacesthrough tightening, for instance, a clasp nut 118, FIG. 8 which isscrewed by the peripheral threads in threads internally existing in therear wall of the slide rest 82.

The clasp nut I I8 is tightened by driving holes drilled in theperiphery of a terminal flange 119, and with its inner end 120 pressesagainst the outer flat face 115 of the right centering ring 114 in orderthat the concave face I16 of the cap of the right ball bearing 108 willcenter this side of the assembly and at the same time adjusts the convexface of the ball bearing cap on the concave face In of the left centerring 109, which fits tightly the recess 1 l l.

The clasp nut I18 is locked in place by means ofa check nut 121tightened by a tool inserted into holes to screw along outer threadsprovided in clasp nut 118.

The carrier ring 106 is centered from the lefthand side by means ofaclasp nut 122 provided with a medium length annular portion 123, whichenters the space between the left bearing 107 and the smooth portion 105of the end of the crossfeed screw 34, and presses against the carrierring 106. The clasp nut 122 is tightened by means of holes drilled inthe periphery of its terminal flange and is locked in place by screwingof a locknut 124. From the right-hand side, the carrier ring 106 iscentered by means of a clasp nut I25, whose long tubular end portion 126projects into the space between the right ball bearing I08 and thesmooth portion 105 of the crossfeed screw 34 and presses against thecarrier ring 106. The clasp nut 125 is tightened by means of holesdrilled in the periphery of its terminal flange and is locked by meansof a check nut 127, tightened through the driving holes.

In the preceding paragraphs were described and numbered the constructiveparts of the apparatus of this invention; a description of the operationwill be now given. The parts of a lathe which strictly do not concernthe indicating counter but are closely related thereto, either becausethey are related to the devices needed for the zero-setting of the latheor because they are conventional parts mentioned for clarity, willreceive additional numerals as this specification continues andreference to parts not previously mentioned is made.

The precision mounting of crossfeed screw 34 by means of the partsabove-described being effected, a device capable of determining thegeometric axis of the main spindle of a lathe must be provided in orderthat the cutting tools may have a zero reference from which the turningdiameter is measured, that is, the distance between the tool and thegeometric axis 89.

FIGS. 9, 10, ll, 12, illustrate a geometric axis determining device 128by means of which the fixing of the axis or imaginary reference line isobtained. The geometric axis determining device 128 comprises a base 129formed as a truncated cone, from the major end of which extends a stem130, the remote end of which forms a half disc 131. The flat faces 132of the half disc 131 coincide with a plane which passes through thecenter axis of the base 129 and through the coinciding axis 89 of themain spindle. In the middle portion between these flat faces 132 arecess 133 is provided, the bottom of which is parallel to the flatfaces 132. Radially drilled in the half disc 131 is a hole into which isfitted a pin 134 of a gauge 135 whose reading is made by means of apointer 136. The geometric axis of said hole is perpendicular to thegeometric axis 89 of the lathe main spindle and lies in the samehorizontal plane. On one end of the pin 134 projecting slightly abovethe bottom wall of the recess 133 an adjustable sensing projection 137is provided.

The plane in which the geometric axis 89 lies is determined by a closefitting of the base 129 of the geometric axis determining device 128 toa conical hole in the main spindle (not shown) of the lathe so that thespindle and the base 129 are coaxial. Close to the flat faces 132 a stop138 shown in FIG. is disposed, which comprises a trapezoidal body with aknurled extension 139 to allow a safe use when handled, and a base face140 absolutely flat which abuts the flat abutment faces 132 of the halfdisc 131. The gauge 135 is zeroed with the sensing projection 137 justtouching reference face 140. Then any contact with said sensingprojection 137 will be indicated by pointer 136, whose zero-setting nowcorresponds to the vertical plane through the geometric axis of thelathe.

Then the tool post 141 on slide 88 (FIG. 11, 12, and 16) must be placedin a position such that the distance from said toolpost 141 to thegeometric axis 89 of the lathe is rigorously determined which will serveas a reference for the tools fitted in the usual manner to the toolpost141, so that a cross feeding of the tool to remove material from theworkpiece is registered in the digital counter 76.

The tool 142 indicated as an example, in FIGS. 15 and 16 must be spaceda certain fixed or measured distance from the zero point selected orfrom the geometric axis 89 of the lathe main spindle, see FIG. 6. Thisdistance can be determined by means ofa setting master bar 143 (FIGS. 11and 12) which is fixed in the toolpost 141, by means of bolts 169 in theposition of a tool. The end 144 of the setting master bar 143 ispositioned so that it just touches the sensing projection 137 of thegauge 135, so that pointer 136 registers with the zero point previouslydetermined.

The operator must then set to zero the indicating elements, that is tosay, the fractional graduated drum 2 and the digital indicating counter76, the former for the fractional values and the latter for the wholenumbers.

The zero setting of the fractional graduation drum 2 is attained byturning the knurled head 20 of the bolt 19, so that the threads 21 areunscrewed from perforation 22 in lock ring 23, loosening the shoulders7, 8 of outer ring 4, respectively from the annular flange 10 of centralannular support 9 and from the lockring 23. The outer ring 4 is free tobe rotated by hand, till the number zero in the graduations 5 registerswith an indexing dash 145 (FIG. 3) adequately marked in the periphery ofthe projecting rim 24 of the support disc 25. Set at zero, the drum 2 islocked again by the driving bolt 19, so that locking ring 4, can onlyrotate with the rotation of the idle feed control shaft 13.

To zero the digital indicating counter 76, the operator unscrews theknurled knob 68, so that the serrations provided in the inner peripheryof the inside flange 69 are disengaged from the serrations provided inthe outer periphery of the flange 59, of the outer shaft 51. Since theknurled knob 68 is secured to the disc 67 an outward linear displacementgiven to the knurled knob 68 is transferred to the disc 67, and thesphere 64 against the spring 65 will get out the recess 63 untilreaching the recess 62, in which position the serrations are dis engagedfrom each other. A turning movement of the knurled knob 68 will rotatethe shaft 60 by means of the key 146 connecting the shaft 60 to the disc67, so that the rotary motion, through the pin 72 is transferred to theconnecting sleeve 71 and to the end 73 of shaft 74 which is the shaftwhich actuates the digital counter 76. The characters can thus be set sothat zero appears on all the wheels of the counter 76 when viewedthrough the aperture 80 of housing 1.

The digital counter 76 is locked by pushing the knob 68 toward thehousing 1, so that subsequently only through the rotation of the outershaft 51 will the characters of the digital readout 76 be changed.

After the zero-setting of the indicating devices digital counter 76 andfractional graduation drum 2-toolpost 141 may be drawn back from thegeometric axis 89, in order that this distance be registered in thedigital counter 76 and the graduations 5 of outer ring 4, so that thetool may be adjusted for operation.

The rapid forward movements and withdrawals are made through theintermediary of the flywheel 3 and its handle 44. The clockwise rotationof the handle will result in forward movement of the tool 142 and thecounterclockwise in the withdrawal thereof relative to the geometricaxis 89. The movement is transferred through the gearwheel 38 to thegearwheel 32 and thus to the crossfeed screw 34 in a reverse sense. Ifthe rotation of flywheel 3 is clockwise, that of the crossfeed screw 34will be counterclockwise. The crossfeed screw rotation motion istransferred to cross-slide nut by rolling the spheres 98, 99 into thechannels provided in the inner hollow of the cross-slide leading nut 90and in the crossfeed screw 34, so that the cross-slide nut 90 isdisplaced lengthwise carrying the cross-slide 88 and the toolpost 141 ina feeding movement.

Adjustment to the graduation drum 2 is made through the outer ring 4locked against the central annular support 9, which is engaged in thecentral bore 11 at the tapered end 12 of the idle feed control shaft 13and locked by means of the locknut 14, the axial displacement of whichis prevented by a screw 17 driven through the split 16. The rotation ofthe fractional graduation drum 2, will be transferred to the idle feedcontrol shaft 13 and from the spline gears 29 to the spur gear 30, screw34, and cross-slide 88. In this example, the speed ratio between splinegears 29 and spur gear 30 is M0 and the pitch of the crossfeed screw 34is 5 mm. so that each complete revolution of the fractional graduationdrum 2 about its axis, corresponds to one-tenth of one turn of gearwheel30, that is to say, an angular movement of 360 or a linear displacementfor the cross-slide 88 with toolpost 141 and tool 142 of mm.

Consequently, [0 complete revolutions of drum 2 about its own axis arenecessary to cause for the cross-slide 88 a linear displacement of 5mm., that is a complete revolution of the crossfeed screw 34 about itsown axis.

The gearing ratio between the gearwheel 32 and the gearwheel 38 is 2:l.Thus, for instance, as the crossfeed screw has a thread pitch of 5 mm.,for each complete revolution of the flywheel 3 a linear feed of 2% mm.,will result for the cross-slide 88, as well as for the toolpost 141.

Since the gearwheel 30 engages the teeth 45 in the intermediate shaft 46the rotation received from the flywheel 3 will be transferred also tothe bevel gear 48 and to the bevel gear 50, causing rotation of theouter shaft 51 and through the clutching of the serrations, rotation ofthe actuating shaft 60 through the key 146, the connecting sleeve 71 andthe shaft 75 of the digital counter 76. This will alter the indicatedcharacters of the respective register wheels, through the dummy wheel77, at each l0 revolutions received.

Since the ratio between the gearwheel 30 and the teeth 45 is l0:l eachcomplete revolution of crossfeed screw 34 with the gearwheel 30 effectedby the flywheel 3 or by the drum 2, produces 10 revolutions of theintermediate shaft 46, and since the ratio between the crown gears 49,50 is 1:1, the outer shaft 51 and the actuating shaft 60 will rotate thedummy wheel 77 10 times in order that the first wheel will pass from onenumber to another.

A workpiece is considered by its diameter for its cutting measurements.It is known that the displacement of the tool towards or the retractionof the tool from the geometric axis 89 is linear and amounts to mm. forone complete revolution of the gearwheel 30 and the crossfeed screw 34about their common axis. Thus, departing from the zero indexed incoincidence with the geometric axis 89 already determined the digitalcounter will register the numeral 10, in consequence of that onerotation that has drawn back the bit of the cutting tool 5 mm. in lineardisplacement. Considering the gearing ratio stated above, the drum 2 andthe outer ring 4 starting from the zero indexed, will rotate 20 timesabout their common axis, the numeral zero of graduations 5 indexingagain the indexing mark 145 engraved in the projecting rim 24.

The graduations 5 are made with the basic graduations 147 in thecircumference of outer ring 4, which amount to 200, each onecorresponding to the 0.005 mm. on the workpiece diameter, to 2% microns(0.0025) of linear displacement of the toolpost 141. Therefore,considering rotation from one basis graduation 147 to the following, thetool 142 will feed a distance equal to a 2.5 thousandth pan of l mm.,since the crossfeed screw 34 has a thread pitch of 5 mm. and hasreceived an angular movement which corresponds to the fivethousandthspart of 1 mm. as a result from the ratio of the engagement of gearwheels29, 30 is 1:10. Every second basis graduation 147 is indicated by alonger dash 148, and corresponds to 0.01 of 1 mm. in the diameter of aworkpiece; further, the larger graduations indicated by the long dash149, in groups of 20 basic divisions, will correspond to 0.1. of 1 mm.in the workpiece diameter; one complete revolution of the drum 2 aroundits axis will correspond to 1 mm. in the diameter of workpiece, or b mm.of linear displacement of toolpost.

After the determination of the zero-setting of the indicatingdevices-the drum 2 and the digital counter 76attention is given to thetoolpost 141 and the tool 142 needed for the cutting operation. The zeroposition of the toolpost has already been determined by the settingmaster bar 143. The toolpost 141 may be drawn back relative to thegeometric axis 89 a given distance which is registered both in thegraduations 5 on drum 2 and the digital counter 76.

The tool 142 must project from post 141 for the same distance as doesthe setting master bar 143. To accomplish this, in the upper surface 150of cross-slide 88 a recess 151 is milled, which is provided with ashoulder 152 perpendicular to the edge of the cross-slide 88. The recessis provided with a series of transverse triangular slots to collect dirtand chips which may fall there.

A tool zero-setting device 153 (FIG. 15 and 16) has its square base 154abutting the shoulder 52, so that no gaps will arise between the matingsurfaces. From the base 154 rises a column 155, which forms a platform156 in the upper end where a gauge 157 capable of linear displacement isapplied. A sensing pin 158 projects from the gauge 157 and ends in asensing flange 159. The gauge 157 has a pointer 160 which will giveindication of the zero-setting as explained hereinafter.

After the base 154 is positively and closely fitted against shoulder152, the operator feeds tool post 141 through the means alreadyexplained, till the digital counter 76 shows again the zeros coincidentwith the geometric axis 89 of the lathe embodying this invention, andpreviously altered by the retraction of the toolpost. In this positionthe end 144 of the setting master bar 143, which is set already asexplained hereinbefore, will merely touch the sensing flange 159 and theoperator then zeros the pointer 160.

The tool 142 with a bit 161 is adjusted at a certain and given height inrelation to a horizontal plane passing through the geometric axis 89,which may be effected by rotating through 90 the geometric axisdetermining device 128 about main axis 89, in order that the bit 161 ofthe tool 142 touches the sensing projection 137 of the gauge 135, nowincident on a horizontal plane. In order that the height of the tool bit161 may be determined for future reference, a tool height fixing device162, see FIGS. 13 and 14, must be employed on the platform 156 of thetool zero-setting device 153, over the gauge 157. This device 162comprises a plate 163 with downward lateral flaps 164, and a triangularprojection 166 in a threaded hole of which is disposed a fine adjustingscrew 167 locked by means of a locknut 168, when touching the tool bit.

The zero-setting of the above-mentioned setting master bar 143 willallow that the tool 142 projects a certain distance from the front faceof toolpost 141. The distance is called the overhang of the tool. Thisoverhang may be enlarged relative to the initial setting of thegeometric axis 89, by the insertion of shims between the vertical facesof the base 154 of the tool zero-setting device 153 and the shoulder152, on the recess 151. Since the readings on the digital counter 76 andthe drum 2 correspond always to the required diameter of the workpiece,the indicating means must be unlocked and set at zero again for a largeroverhang of the tool.

When the tool tip 161 lies exactly on the geometric axis 89 of thelathe, the position of the tool may be fixed by means of the bolts 169to the tool post 141, the toolpost 141 being then drawn back to providethe necessary space for the fitting of the workpiece in the lathe.

Summarizing, member 128 is mounted on the main spindle coaxial with themain axis 89 so that sensor 137 is located in the same when stop face132 abuts abutment faces 131. Gauge 135 is now manually set to zero.

Master bar 143 is moved with slide 88 on toolpost 141 until its endabuts sensor 137, and gauge 135 has zero indication. Since slide 88 isnow in zero" position counter means 2, 76 are manually set to zeroindication.

The position of the master bar 143 in relation to slide 88, 141 ismeasured by tool-setting gauge 157 which has a fixed position relativeto toolpost 141 of slide 88 due to support 153 abutting shoulder 152.Gauge 157 is preferably set to zero indication.

A tool 142, 161 is substituted for the master bar 143 and adjusted untilits tip 161 engages gauge 154 indicating zero, or the same indication asbefore.

When the tool slide 88 is now withdrawn, counter means 2, 76 indicatethe distance of the tip 161 of the tool 142 from the main axis 89 and aworkpiece can be accurately cut to a desired diameter by observing thediminishing indications of counter means 2, 76 during advance of theslide 88 with the tool toward and into the workpiece. The distance whichthe tool is withdrawn is registered in subdivisions of millimeters indrum 2, and in millimeters in the digital counter 76 in correspondencewith the counterclockwise manual rotation of flywheel 3, which draws thecross-slide 88 away from the geometric axis 89 of the lathe main spindlein the established ratio, that is to say, to each complete turn offlywheel 3 about its axis, crossfeed screw 34 is given an angulardisplacement of and cross-slide 88 travels a linear distance of 2% mm.

This displacement is registered as double this amount, to correspond toincrease in the diameter of 5 mm., due to the fact that the gearing forthe digital counter 76 is arranged so that during the return of the tool142 the indicated amount is increased above the original zeros set, andby the feed of the tool the indicated amount is diminished in theregistered total.

Thus, to each distance of 1 mm. run by the cross-slide 88 as drawn back,the digital counter 76 will register, increasing from 000 in steps ofone digit, the number corresponding to twice this amount, that is thedigit two. To make clearer the explanation a practical example is givenin the following: the digital counter 76 increases by two units for thefirst millimeter movement of the cross-slide 88; four for the secondmillimeter; six for the third, and so on, till the travel of the tool iscompleted by the linear displacement of the cross-slide 88, asexplained. The odd numbers follow the same ratio, that is, the numeralone for the first /z mm.; the numeral three for l mm. and V1; thenumeral live for the 2% mm., etc. To sum up. let it be supposed that atthe digital counter 76 appears the numeral 200. This means that the tool142 has been drawn back from the geometric axis linearly, by an amountof 100 mm., which is registered for the adaptation of the workpiece ofthis example.

The approach of the tool 142 relative to the geometric axis 89, whichwas obtained by a clockwise rotation of the flywheel 3, will subtractfrom the numeral 200 in the digital counter, an amount equal to twicethe distance in millimeters of the travel of the tool 142 toward thegeometric axis.

As a concrete example, let it be supposed that the workpiece biank has adiameter of 152 mm. This diameter will be registered in the digitalcounter 76 upon the tool bit 161 touching the periphery of the blank. Inorder to accomplish this, the cross-slide 88 must travel a distance of24 mm. from the position in which the digital counter registers 200 mm.As clearly stated, counting is made by the diameter. 80 the travel ofthe cross-slide 88 towards the geometric axis 89 by the amount of 24 mm.will subtract 48 units from the numeral 200 registered previously in thedigital readout 76.

Let it be supposed further that the workpiece is required to have afinal diameter of H mm. Having in mind such elements as metal hardness,tool bit, cutting speed and so on the operator calculates the cuttingdepth of the successive tool passages needed to withdraw a coat of 21mm. in the radius of the blank, in order that the finished workpiece hasa diameter of 1 l0 mm.

Let it be supposed yet that the operator wishes to withdraw fromworkpiece a further coat of twenty-five thousandths of 1 mm., i.e.,0.025 mm., after the final diameter of 110 mm. is obtained. The operatoroperates the lathe for the cutting as explained, until the numeral 1appears in digital counter 76.

The zero mark of the graduations 5, on the outer ring 4 will registerwith the indicating mark 145. By an angular motion of outer ring 4, theoperator turns drum 2 till the dash corresponding to five graduations148 registers with the indicating mark 145, resulting in the tool 142being moved a further distance of 0.025 mm. and a reduction of 0.025 mm.in the radius of the workpiece.

On the other hand the operator wishes to leave a coat of twenty-fivethousandths of l mm., when the digital readout 76 almost registers thenumeral 110, the operator stops the tool feed at the ninety-fifthgraduation 148 before the zero registers as the indicating mark 145 inprojecting rim 24, resulting that in the blank diameter a coat of 0.05of l mm. remains prior to the blank being the exact diameter of l 10 mm.

The corresponding change of the graduations 5 on fractionary graduationdrum 2 and the adaptation of digital readout 76, may adjust the deviceto read in inches.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofmethods of presetting tools differing from the types described above.

While the invention has been illustrated and described as embodied in amethod of presetting a tool in a lathe by means of gauges and amasterbar, it is not intended to be limited to the details shown, sincevarious modifications and structural changes may be made withoutdeparting in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat. from the standpoint of prior art. fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims.

lclaim:

l. The method of presetting a tool for measured movements comprising thesteps of moving a cross tool slide of a lathe transversely to the mainaxis of the lathe with a master bar until the end of the latter islocated in said main axis of the lathe; setting counter means whichindicate movements of said slide and master bar to zero indication;mounting a toolsetting gauge on said slide in a position in which asensing member of said gauge touches said end of said master bar causingan indication of said tool-setting gauge; substituting a tool for saidmaster bar on said slide and adjusting the position of the tool untilthe same touches said sensing member at the same indication of saidtool-setting gauge as said master bar; withdrawing said cross tool slideand tool so that said counter means indicate the distance between thetool and said main axis; removing said tool-setting gauge, and settingup a workpiece for rotation about said main axis; and advancing thecross tool slide and said tool until said workpiece is cut by said toolto a predetermined diameter indicated by said counter means.

2. The method of claim I wherein the step of moving the cross tool slideuntil the master bar is located in said main axis includes placing agauge in said main axis and setting the gauge to zero indication; andmoving said cross tool slide until said end of said master bar touchessaid gauge at zero indication.

3. The method of claim 2 wherein said step of placing said gauge in saidmain axis includes setting up a reference stop face in said main axis,and placing a sensor of said gauge in touch with said stop face beforesetting said gauge to zero indication.

4. The method of claim 3 wherein said reference stop face is located ina vertical plane passing through said main axis, and abuts also anabutment face of said gauge when in touch with said sensor.

5. The method of claim 4 comprising the step of turning said gauge aboutsaid main axis so that-said abutment face and sensor are located in ahorizontal plane passing through said main axis; and positioning saidtool until the same touches said sensor and is located in saidhorizontal plane.

6. The method of claim 5 comprising determining the height of the toolduring subsequent operations by a height limiting stop set in accordancewith the position of the tool in said main axis obtained by said turnedgauge.

7. The method of claim 1 wherein said counter means include a counterfor units and a counter for fractions of units so that distancestraversed by said tool are indicated in units and fractions.

8. The method of claim 1 including setting said tool-setting gauge tozero indication while touched by said master bar; and adjusting theposition of said tool until said tool-setting gauge indicates zero.

i l t I

1. The method of presetting a tool for measured movements comprising thesteps of moving a cross tool slide of a lathe transversely to the mainaxis of the lathe with a master bar until the end of the latter islocated in said main axis of the lathe; setting counter means whichindicate movements of said slide and master bar to zero indication;mounting a tool-setting gauge on said slide in a position in which asensing member of said gauge touches said end of said master bar causingan indication of said tool-setting gauge; substituting a tool for saidmaster bar on said slide and adjusting the position of the tool untilthe same touches said sensing member at the same indication of saidtool-setting gauge as said master bar; withdrawing said cross tool slideand tool so that said counter means indicate the distance between thetool and said main axis; removing said tool-setting gauge, and settingup a workpiece for rOtation about said main axis; and advancing thecross tool slide and said tool until said workpiece is cut by said toolto a predetermined diameter indicated by said counter means.
 2. Themethod of claim 1 wherein the step of moving the cross tool slide untilthe master bar is located in said main axis includes placing a gauge insaid main axis and setting the gauge to zero indication; and moving saidcross tool slide until said end of said master bar touches said gauge atzero indication.
 3. The method of claim 2 wherein said step of placingsaid gauge in said main axis includes setting up a reference stop facein said main axis, and placing a sensor of said gauge in touch with saidstop face before setting said gauge to zero indication.
 4. The method ofclaim 3 wherein said reference stop face is located in a vertical planepassing through said main axis, and abuts also an abutment face of saidgauge when in touch with said sensor.
 5. The method of claim 4comprising the step of turning said gauge 90* about said main axis sothat said abutment face and sensor are located in a horizontal planepassing through said main axis; and positioning said tool until the sametouches said sensor and is located in said horizontal plane.
 6. Themethod of claim 5 comprising determining the height of the tool duringsubsequent operations by a height limiting stop set in accordance withthe position of the tool in said main axis obtained by said turnedgauge.
 7. The method of claim 1 wherein said counter means include acounter for units and a counter for fractions of units so that distancestraversed by said tool are indicated in units and fractions.
 8. Themethod of claim 1 including setting said tool-setting gauge to zeroindication while touched by said master bar; and adjusting the positionof said tool until said tool-setting gauge indicates zero.